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S-AES17 or not ?
Old 20th January 2009
  #1
Gear Maniac
 

S-AES17 or not ?

what is recommended for RMS vaules

S-AES17 or not ?
when
S-AES17 is recommended ?

wavelab has switchable
S-AES17
Digicheck - seems to have
S-AES17 switched off .




Old 20th January 2009
  #2
Mastering
 

Quote:
Originally Posted by cichy View Post
what is recommended for RMS vaules

S-AES17 or not ?
when
S-AES17 is recommended ?

wavelab has switchable
S-AES17
Digicheck - seems to have
[FONT=Verdana, Arial, Helvetica, sans-serif][SIZE=2]S-AES17 switched off .
This is what standards are for :-).

When choosing any of the K-System scales in Digicheck, AES-17 is automatically checked and cannot be unchecked. Digicheck calls this "RMS + 3 dB", which is misleading because the official definition of RMS for dB, according to the standard, defines the dB reference for the RMS sinewave to be the SAME as for the the peak measurement.

What confused the mathematical designers of some of the RMS meters is the fact that RMS is 0.707 of the peak value of a sinewave. They then figured that this is 3 dB less and so then they figured the RMS value should be 3 dB lower. HOWEVER, it is the REFERENCE that counts, and by making the reference 0 dB for all types of waves, it makes it convenient and consistent for use with program material as well as sine wave test signals. The way it's always been for 40-60 years----before digital audio came on the scene and some designers who had not used the older analog meters.

I believe the same is true of Wavelab 6 when choosing a K-system meter, there's no way to change that because it is a standard.

AES-17 has a precedent going back over 40-50 years. It was only the introduction of RMS meters and averaging meters by software engineers who had no idea of the precedent that introduced the problem. Hands down, AES-17, which is actually IEC 61606:1997 is the only way to go. The idea is that the dB reference for any wave, and any wave method of measurement, whether it be triangle, square or sine, averaging, RMS or peak, should be the same.

Remember that Dorrough meters (as close to a standard as anything you encounter) have followed this approach for many years long before digital audio came into prominence. And that the language is always a sine wave reference, so that 0 dB is 0 dB is 0 dB.

In the analog domain, for 40-50 or more years, peak reading meters, including those from the BBC, were always aligned with a 0 dBu 0.775 v RMS sine wave. Then, with music, you would say that the peak level is "0 dB" if the meter then read 0 dB. Test meters (mostly from European manufacturers such as B&K and I believe a few from Genrad) and others that had peak characteristics, were aligned and some of them even read "dBm" on their scales.

BK
Old 28th May 2011
  #3
Lives for gear
 
Laurend's Avatar
 

That's the famous crest factor.
Crest factor - Wikipedia, the free encyclopedia
Old 28th May 2011
  #4
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Nordenstam's Avatar
 

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